1. Differentiate between polling and vector
2. In the storage devices hierarchy, why are the
top devices faster than the lower devices? Why is a register faster than
1. An interrupt is a signal from a device linked or attached to a computer
or from a program within the computer that requires the operating system to stop and figure out what action or event to carry
out next. The types are:
Polling interrupt: It is a clearly defined type of input/output
interrupt that informs or reports the part of the computer containing the
input/output interface that a device is fully prepared or in a suitable state
to be read or handled but does not point out or suggest which device. Polling
means to give a signal out to every device
to ascertain or establish which one made the request.
Vector interrupt: This is a substitute or suitable replacement for
polling interrupt. It is an interrupt signal that includes the identity (name
and location) of the device sending the interrupt signal unlike the polling
interrupt. Vector interrupts have specific locations inside the memory address
space which directs to a routine able to efficiently handle the dealing with
interrupts from that device.
The top part of the storage device hierarchy are faster than the
devices even though the lower ones are even larger, this is because for example
the register is an extremely important
internal CPU memory. So accesses
to registers are easier and faster than other kind
of memory access.
Smaller memories are always faster than larger ones, in addition also require
fewer bits to address. That is the closer the device is to the computer (if it
is an internal part of or if it is an external part of the computer) the faster
it is to memory access. Hence smaller memories equal faster access
while larger memories equal slower access.